Devices and methods for left atrial appendage closure

ABSTRACT

Described here are devices, systems, and methods for closing the left atrial appendage. The methods described here utilize a closure device for closing the left atrial appendage and guides or expandable elements with ablation or abrading elements to ablate or abrade the left atrial appendage. In general, these methods include positioning a balloon at least partially within the atrial appendage, positioning a closure assembly of a closure device around an exterior of the atrial appendage, inflating the balloon, partially closing the closure assembly, ablating the interior tissue of the atrial appendage with the inflated balloon, removing the balloon from the atrial appendage, and closing the atrial appendage with the closure assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 61/898,382, filed on Oct. 31, 2013, which is incorporated byreference herein in its entirety.

FIELD

This invention relates generally to systems and methods for closingtissue such as the left atrial appendage.

BACKGROUND

Atrial fibrillation is a common problem that afflicts millions ofpatients. Atrial fibrillation often results in the formation of athrombus, or clot, in the appendage of the left atrium. This presents aproblem, inasmuch as the thrombus can dislodge and embolize to distantorgans, which may result in adverse events such as a stroke. For thisreason, most patients with atrial fibrillation are treated with one ormore blood thinners to help prevent the formation of a thrombus. Bloodthinners, however, can present health risks of their own, especially inthe elderly. These risks, such as bleeding, often require a user to makesignificant lifestyle changes.

Several methods have been developed to address the potential problem ofthrombus formation in the left atrial appendage. One such methodincludes suturing the left atrial appendage along the base or ostialneck where it joins the atrial chamber. In this way, blood flow into theatrial appendage is cut off, eliminating the risk of thrombus formationtherein. This is typically done through open-heart surgery, which limitsthe availability of the procedure to those who are at a particularlyhigh risk, or who are otherwise undergoing an open-heart procedure. Inaddition, open-heart surgery requires general anesthesia and has anumber of well-known risks, making it less desirable.

Other methods have also been investigated. These methods include methodsof stapling the base of the appendage and methods of filling theappendage with a space occupying or occluding member. Stapling is notpreferred given the fragility of the appendage and its tendency torupture, while occlusion devices may not effectively prevent all bloodflow into the appendage.

Additional devices and methods for closing the left atrial appendage orother suitable tissues would therefore be desirable. In particular,devices and methods for closing the left atrial appendage usingminimally invasive, intravascular, or a combination of these techniques,would be desirable in order to avoid the need for opening the chest. Ofcourse, additional devices for use in open surgical procedures aredesirable as well, especially when those devices offer additionaladvantages over standard devices.

BRIEF SUMMARY

Described here are devices, systems, and methods for closing an atrialappendage such as the left atrial appendage. In some instances, themethods described here may comprise positioning a balloon at leastpartially within an interior of the atrial appendage and positioning aclosure assembly of a closure device around an exterior of the atrialappendage. The methods may further comprise inflating the balloon atleast partially within the interior of the atrial appendage, andpartially closing the closure assembly to pull interior tissue of theatrial appendage into contact with the inflated balloon. In some ofthese variations, the methods may further comprise ablating the interiortissue of the atrial appendage with the inflated balloon, removing theballoon from the atrial appendage, and closing the atrial appendage withthe closure assembly.

In some variations, the method may further comprise positioning a distalend of a first guide element in the interior of the atrial appendage andpositioning a distal end of a second guide element in a pericardialspace externally of the atrial appendage. In some instances, the firstguide element and the second guide element may each comprise a magnet,and the method may further comprise aligning the first guide element andthe second guide element across tissue of the atrial appendage. In somevariations, positioning the closure device may include advancing theclosure device along the second guide element. The balloon may be partof the first guide element, or may be part of a balloon catheter. Ininstances where the balloon is part of the balloon catheter, positioningthe balloon may comprise advancing the balloon catheter along the firstguide element.

In some variations the balloon may comprise an electrode positioned onan exterior surface of the balloon, and ablating the interior tissue ofthe atrial appendage may comprise ablating the interior tissue of theatrial appendage with the electrode. In other variations, the balloonmay comprise at least two electrodes and the method may further comprisemonitoring a tissue parameter with at least one of the electrodes duringablation of the interior tissue. In yet other variations, ablating theinterior tissue of the atrial appendage may comprise ablating theinterior tissue of the atrial appendage using heated fluid contained inthe balloon. In some variations the method may further comprisereleasing a suture loop from the closure assembly to hold the atrialappendage closed. Additionally or alternatively, in some variations theclosure assembly may comprise an electrode, and the method may furthercomprise ablating an exterior of the atrial appendage with theelectrode. In some instances, the method may further comprisecryoablating an exterior surface of the atrial appendage with theclosure assembly.

In other variations, the methods described here may comprise positioninga distal end of a first guide element in the interior of an atrialappendage such as the left atrial appendage, positioning a distal end ofa second guide element in a pericardial space externally of the atrialappendage, and advancing a closure assembly of a closure device aroundan exterior of the atrial appendage along the second guide. In some ofthese variations, the method may further comprise withdrawing the firstguide element from the interior of the atrial appendage and closing theatrial appendage with the closure assembly. The method may furthercomprise advancing a portion of the first guide member into contact withtissue around the ostium of the closed atrial appendage, and ablatingthe contacted tissue with the first guide member.

In some of these methods, the first guide element and the second guideelement may each comprise a magnet, and the method may further comprisealigning the first guide element and the second guide element acrosstissue of the atrial appendage. In some variations, the first guideelement may comprise a balloon. In some of these variations, positioningthe distal end of the first guide element may comprise positioning theballoon at least partially inside the atrial appendage. In somevariations, the method may further comprise advancing a balloon catheteralong the first guide element to position a balloon at least partiallyinside the left atrial appendage. In some of these variations, theballoon may comprise an electrode positioned on an exterior surface ofthe balloon, and the method may further comprise ablating interiortissue of the atrial appendage using the electrodes. In some variations,the balloon may comprise at least two electrodes and the method mayfurther comprise monitoring a tissue parameter with at least one of theelectrodes during ablation of the interior tissue. In some instances,the method may further comprise cryoablating interior tissue of theatrial appendage using the balloon or ablating interior tissue of theatrial appendage using the balloon while the balloon contains heatedfluid.

In some of these methods, the first guide element comprises an electrodepositioned at the distal end of the first guide element. Additionally oralternatively, the method may further comprise advancing a wire from adistal end of the first guide element, wherein advancing a portion ofthe first guide member into contact with tissue around the ostium of theclosed atrial appendage comprises advancing the wire into contact withthe tissue around the ostium of the closed atrial appendage. In some ofthese variations, the wire may be a j-tip wire or a coiled wire. In someinstances, the method may further comprise cryoablating the tissuearound the ostium with the wire. In some variations, the closureassembly may comprise one or more electrodes, and the method may furthercomprise ablating an exterior of the atrial appendage with the one ormore electrodes. In other variations, the method may further comprisecryoablating an exterior surface of the atrial appendage with theclosure device.

In still other variations of the methods described here, the methods maycomprise advancing a distal end of a first device in the interior of anatrial appendage such as the left atrial appendage, wherein the firstdevice comprises a shaft, a balloon, and an electrode or abradingelement positioned on the shaft proximally of the balloon, andpositioning the balloon in the atrial appendage. The method may furthercomprise advancing a closure assembly of a closure device around anexterior of the atrial appendage, partially closing the closure assemblyto place interior tissue of the atrial appendage into contact with theelectrode or abrading element, and ablating or abrading the interiortissue of the atrial appendage with the electrode or abrading element.In some variations, the method may further comprise removing the firstdevice from the atrial appendage; and closing the atrial appendage withthe closure assembly. In some of these methods, the first device maycomprise two or more electrodes and the method may further comprisemonitoring a tissue parameter with at least one of the electrodes duringablation of the interior tissue. In some variations, the closureassembly may comprise an electrode, and the method may further compriseablating an exterior of the atrial appendage with the electrode.

In yet other variations of the methods described here, the methods maycomprise positioning a closure assembly of a closure device around anexterior of the atrial appendage, wherein the closure assembly comprisesa snare, a suture loop, a retention member releasably connecting thesuture loop and the snare, and an electrode on the snare between a fixedend of the snare and the retention member, closing the closure assemblyto close the atrial appendage, ablating exterior tissue of the atrialappendage with the electrodes, and releasing a suture loop from theclosure assembly to hold the atrial appendage closed.

Also described here are systems for closing an atrial appendage. In somevariations, the systems may comprise a catheter that may be configuredto be advanced endovascularly into the interior of a heart, and aclosure device that may be configured to be advanced into a pericardialspace. The catheter may comprise an expandable member at a distal end ofthe catheter and the expandable member may be configured to ablateand/or abrade tissue. In some of these systems, the expandable membermay be a balloon. The closure device may comprise a lumen therethrough,a handle, and a snare loop assembly. The snare loop assembly may extendfrom a distal end of the elongate body and may comprise a snare, asuture loop, and a retention member that may be configured to releasablycouple the snare and the suture loop. In some variations, the snare mayfurther comprise an electrode between a fixed end of the snare and theretention member, and the electrode may be configured to ablate anexterior of the atrial appendage. In yet other variations, the snare maybe configured to cryoablate an exterior of the atrial appendage.

In some variations, the system may further comprise a first guideelement that may be configured to be advanced into the interior of theatrial appendage, and a second guide element that may be configured tobe advanced into a pericardial space. In some instances, the secondguide element may be slideably disposed within the lumen of the closuredevice to advance the closure device into the pericardial space. In somevariations, the catheter may be part of the first guide element. In somesystems, the catheter may comprise a lumen therethrough and the firstguide element may be slideably disposed within the lumen of the catheterto advance the catheter into the interior of the heart.

In some systems, the expandable member may comprise at least oneelectrode positioned on an exterior surface of the expandable member andthe expandable member may be configured to ablate interior tissue withthe at least one electrode. In some instances, the expandable member maycomprise a balloon and the at least one electrode may circumferentiallysurround the exterior surface of the balloon. In some of these systems,one electrode may circumferentially surround the exterior surface of theballoon. In other systems, the expandable member may comprise at leasttwo electrodes and at least one electrode may be configured to monitorat least one tissue parameter during ablation of the interior tissue. Inthese systems, the at least one tissue parameter may comprise at leastone of: temperature, ECG signals, and/or the absence of ECG signals. Insome variations, the expandable member may be inflated with cryogenicfluid and may be configured to cryoablate interior tissue. In yet othervariations, the catheter may further comprise a shaft on which theexpandable member is mounted, the shaft may comprise at least oneelectrode within the expandable member, and the expandable member may beconfigured to ablate interior tissue with fluid heated by the at leastone electrode.

In some variations of the systems described here, the system maycomprise a first guide element that may be configured to be advancedinto the interior of the atrial appendage, a second guide that may beconfigured to be advanced into a pericardial space, and a closure devicethat may be configured to be advanced into a pericardial space. Thefirst guide element may comprise a shaft and an expandable member, andthe shaft may comprise an ablating and/or abrading element positionedproximally of the expandable member. In some of these systems, theexpandable member may be a balloon. The closure device may comprise anelongate body that may comprise a lumen therethrough, a handle, and asnare loop assembly. The snare loop assembly may extend from a distalend of the elongate body and may comprise a snare, a suture loop, and aretention member that may be configured to releasably couple the snareand the suture loop.

In some variations, the first and second guide elements may eachcomprise a magnet and may be configured to align across tissue of theatrial appendage. In some instances, the second guide element may beslideably disposed within the lumen of the closure device to advance theclosure device into the pericardial space. Additionally oralternatively, the ablating and/or abrading element may be an electrodeand the first guide may be configured to ablate interior tissue of theatrial appendage with the electrode. In some systems, the interiortissue of the atrial appendage may be tissue around an ostium of theatrial appendage. In some variations, the ablating and/or abradingelement may comprise at least two electrodes and at least one electrodemay be configured to monitor at least one tissue parameter duringablation of the interior tissue. In some of these variations, the atleast one tissue parameter may comprise: temperature, ECG signals,and/or the absence of ECG signals. In some instances, the snare mayfurther comprise an electrode between a fixed end of the snare and theretention member, and the electrode may be configured to ablate anexterior of the atrial appendage. In yet other instances, the snare maybe configured to cryoablate an exterior surface of the atrial appendage.

In yet other variations of the systems described here, the system maycomprise a first guide element that may be configured to be advancedinto the interior of the atrial appendage, a second guide element thatmay be configured to be advanced into a pericardial space, a closuredevice that may be configured to be advanced into a pericardial space,and an ablating or abrading element that may be configured to ablate orabrade interior tissue of an atrial appendage. In some instances, theablating or abrading element may comprise a j-tip, coiled, orball-tipped wire. In some variations, the ablating or abrading elementmay be configured to cryoablate interior tissue of an atrial appendage.

The first guide element may comprise a proximal end, a distal end, alumen therethrough, and a magnet on the distal end. The second guideelement may comprise a proximal end, a distal end, and a magnet on thedistal that may be configured to align the second guide element with thefirst guide element across tissue. In some variations, the first guideelement may further comprise an expandable member and in some instances,the expandable member may be a balloon. The ablating or abrading elementmay be configured to be slideably disposed within a lumen of the firstguide element and may be advanced from a distal end thereof. The secondguide element may also be configured to be slideably disposed within alumen of the closure device to advance the closure device into thepericardial space.

The closure device may comprise an elongate body that may comprise alumen therethrough, a handle, and a snare loop assembly. The snare loopassembly may extend from a distal end of the elongate body and maycomprise a snare, a suture loop, and a retention member that may beconfigured to releasably couple the snare and the suture loop. In somevariations, the snare may further comprise an electrode between a fixedend of the snare and the retention member, and the electrode may beconfigured to ablate an exterior of the atrial appendage. In yet othervariations, the snare may be configured to cryoablate an exterior of theatrial appendage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a distal end of an illustrative variation of a closuredevice having a snare loop assembly.

FIG. 2 shows a cross-sectional side view of the closure device of FIG.1.

FIG. 3 is a perspective view of an illustrative closure device asdescribed here.

FIG. 4 depicts an illustrative variation of a system for closing theleft atrial appendage.

FIGS. 5A-5C depict side views of different variations of expandablemember catheters suitable for use with the systems described here.

FIGS. 6A-6C depict an illustrative method of closing the left atrialappendage as discussed here.

FIGS. 7A-7D depict side views of illustrative variations of devicessuitable for use with the systems described here.

FIGS. 8A and 8B depict an illustrative method of closing the left atrialappendage as described here.

FIGS. 9A and 9B depict side views of illustrative variations of guideelements suitable for use with the systems described here.

FIGS. 10A-10C depict variations of methods as described here.

FIGS. 11A-11C, 12A-12C, and 13A-13C depict cross-sectional side views ofthree variations of closure devices as described here.

FIGS. 14A-14F depict variations of expandable members suitable for usewith the systems described here.

FIGS. 15A and 15B depict cross-sectional side views of a variation of anexpandable member catheter as described here.

DETAILED DESCRIPTION

Described here are systems and methods for closing the left atrialappendage. Generally, the systems and methods are configured to ablateor abrade left atrial appendage tissue before, during, or after the leftatrial appendage closure procedure. In some instances, the left atrialappendage tissue may be ablated to electrically isolate the left atrialappendage from the heart. For example, for patients suffering fromatrial fibrillation, electrical isolation of the left atrial appendagemay limit the ability for asynchronous heart signals generated in theleft atrial appendage to reach surrounding heart tissue. Additionally oralternatively, ablation or abrasion of left atrial appendage tissue mayinduce an inflammatory response from the left atrial appendage tissue,which may result in healing that may result in tissue fusion orotherwise help maintain closure of the left atrial appendage.

Generally, the left atrial appendage may be closed using one or more ofthe systems described in U.S. patent application Ser. No. 13/490,919,filed on Jun. 7, 2012 and titled “TISSUE LIGATION DEVICES AND TENSIONINGDEVICES THEREFOR,” the content of which is hereby incorporated byreference in its entirety. FIG. 4 shows an illustrative variation of aclosure system (400) that may be used to close the left atrialappendage. As shown there, the system may comprise a first guide element(402), a second guide element (404), an expandable member catheter(406), depicted here as a balloon catheter, and a closure device (408).Generally, the first and second guide elements may be configured to bepositioned in the body and to act as guides for the advancement ofdevices in the body. For example, as shown in FIG. 4, a distal portionof the first guide element (402) may be introduced into the vasculature(e.g., via a femoral access site, brachial access site, or the like) andadvanced into a heart (410) of a patient. In some instances, the firstguide element (402) may be advanced to position a distal end of thefirst guide element (402) in the left atrial appendage (412). A proximalportion of the first guide element (402) may remain outside of the bodysuch that one or more devices may be advanced along the first guideelement (402) and into the body (e.g., the first guide element (402) maybe slideably disposed within a lumen of a device such that the devicemay travel along the first guide element (402)). The device may beadvanced along the first guide element (402) to position a distalportion of the device in the left atrium (414) or the left atrialappendage (412).

Similarly, a distal portion of the second guide element (404) may bepositioned externally of the heart (410). For example, the second guideelement (404) may be introduced into the body through an access point(e.g., intercostal access via a sternotomy, thoracostomy, orthoracotomy, right of the xiphoid process and pointed towards thepatient's left shoulder, or in the costal cartilage or xiphoid processitself) and advanced to position a distal end of the second guideelement into the pericardial space (416). A proximal portion of thesecond guide element (404) may remain outside of the body such that oneor more devices may be advanced along the second guide element (404) toposition a distal portion of the device in the pericardial space (416)(e.g., the second guide element (404) may be slideably disposed within alumen of the device such that the device may travel along the secondguide element (404)).

In some variations, the first guide element (402) and the second guideelement (404) may be configured to align themselves across tissue of theheart. For example, in some variations, the first guide element (402)and the second guide element (404) may each comprise a magnet (418) ator near a distal end of the guide element. When the first guide element(402) and the second guide element (404) are positioned on oppositesides of heart tissue, the magnet (418) of the first guide element (402)may be attracted to the magnet (418) of the second guide element (404)(and vice versa), which may align the first and second guide elements.In some instances, as shown in FIG. 4, a distal end of the first guideelement (402) may be positioned in the left atrial appendage (412), anda distal end of the second guide element (404) may be aligned with thefirst guide element (402) across tissue of the left atrial appendage(412) (e.g., via magnets). While shown in FIG. 4 as being aligned viamagnets (418), the first guide element (402) and second guide element(404) may be manually aligned (e.g., via manipulation of the first andsecond guide elements under visualization such as fluoroscopy). Itshould also be appreciated that first and/or second guide elements maybe any member suitable for advancement through the vasculature or thepericardial space, such as, for example, a catheter, wire, hollow wire,or the like.

The expandable member catheter (406) is generally configured to beadvanced for endovascularly into the heart (410). For example, in somevariations, the expandable member catheter (406) may be configured to beadvanced along the first guide element (402) (e.g., in an over-the-wireconfiguration, a rapid-exchange configuration, or the like) to positiona distal portion of the expandable member catheter (406) in the heart(410) (e.g., in the left atrium (414), the left atrial appendage (412)or the like). The expandable member catheter (406) may comprise anexpandable member, for example, an inflatable balloon (420) or otherexpandable structure. The balloon (420) or expandable member may bepositioned at least partially inside of the left atrial appendage (412),and may be expanded. When expanded, the balloon (420) or expandablemember may press against or otherwise support a portion of the leftatrial appendage (412). Additionally or alternatively, the balloon (420)or expandable member may be filled or coated with a contrast material,which may assist in visualization of the left atrial appendage (412)during the closure procedure. When the expandable member catheter (406)is positioned along a portion of the first guide element (402), theexpandable member catheter (406) may be advanced over the first guideelement (402) after the first guide element (402) has been positioned,or may be positioned simultaneously with the first guide element (402).In other variations, the system (400) may not comprise an expandablemember catheter (406) separate from first guide element (402). In someof these variations, the first guide element (402) may comprise aninflatable balloon (420) or an expandable member, which may be expanded(e.g., in the left atrial appendage (412) as discussed above). In othervariations, the system (400) may not include an expandable memberpositioned in the left atrial appendage (412).

The closure device (408) is generally configured to close the leftatrial appendage. The closure device (408) may be advanced along thesecond guide element (404) to position a distal portion of the closuredevice (408) in the pericardial space (416). Advancement of the closuredevice (408) into the pericardial space (416) may also position aclosure assembly (422) (such as a snare loop assembly, as will bediscussed in more detail below) around an external portion of the leftatrial appendage (412). The closure assembly (422) may be actuated toclose the closure assembly (422) around the left atrial appendage (412),which may at least partially close the left atrial appendage (412). Insome instances, the closure assembly (422) may be at least partiallyreopened to allow the left atrial appendage (412) to at least partiallyreopen and/or to remove the closure assembly (422). In some variations,the closure assembly (422) may be configured to release a suture loop orother deployable loop which may hold the left atrial appendage (412) ina closed configuration.

FIG. 3 depicts one illustrative variation of a closure device (300) asdescribed here. As shown there, the closure device (300) may comprise asnare loop assembly (302), an elongate body (304), and a handle (306).Generally, a portion of the snare loop assembly (302) extends from adistal portion of the elongate body (304) to form a continuous loop(308), which may allow the snare loop assembly (302) and the elongatebody (304) to encircle tissue placed in the loop (308). The handle (306)may be used to control and actuate the snare loop assembly (302) throughthe elongate body (304) in order to increase or decrease the size of theloop (308) (e.g., increase or decrease the loop's circumference ordiameter). For example, the handle (306) may advance a portion of thesnare loop assembly (302) out of the elongate body (304) to increase thesize of the loop (308), or may withdraw a portion of the snare loopassembly (302) into the elongate body (304) to decrease the size of theloop (308). Accordingly, the size of the loop (308) may be increased toallow the snare loop assembly (302) to be placed around tissue. Oncearound tissue, the size of the loop (308) may be decreased toligate/close tissue (e.g., such as the left atrial appendage, asdiscussed above with respect to FIG. 4). The size of the loop (308) maythen be increased to allow the tissue to be at least partially unclosedand/or to disengage the snare loop assembly (302) from tissue.

The snare loop assemblies of the closure devices described heregenerally comprise a snare and a suture loop releasably coupled thereto.For example, FIG. 1 shows a distal portion of an illustrative variationof a closure device (100) comprising a snare loop assembly (101) and anelongate body (108) having a tip (110). As shown there, the snare loopassembly (101) may comprise a snare (102), a suture loop (104), and aretention member (106), and may be disposed relative to the elongatebody (108) such that at least a portion of the snare loop assembly (101)extends from the elongate body (108) (e.g., out of tip (110)). The snareloop assembly (101) is shown in FIG. 1 in an open configuration, and theportion of snare loop assembly (101) extending out of elongate body(104) may form a loop (109) having an aperture (112) therethrough, suchas discussed above. The loop (109) and corresponding aperture (112) maybe defined by one or more components of the snare loop assembly (101)(e.g., the snare), and may be suitable for encircling tissue such as theleft atrial appendage.

Generally, the snare (102) may be actuated (e.g., by a portion of ahandle or other control portion of the closure device) to control thesize of the loop (109) of the snare loop assembly (101). For example,FIG. 2 shows a cross-sectional side view of the closure device (100). Asshown there, the elongate body (108) may comprise a first lumen (114)and a second lumen (116). One end (118) of the snare (102) may befixedly attached to the elongate body (108) (e.g., attached to the tip(110)), while a second end (not shown) of the snare may pass through thefirst lumen (114), where it may be operatively attached to a snarecontrol (not shown). The snare control may be configured to advance orretract the snare (102) relative to the elongate body (108), which maycontrol the amount of the snare (102) (and with it, the snare loopassembly (101)) extending from the elongate body (108). This in turn maycontrol the size (e.g., circumference or diameter) of the loop (109) ofthe snare loop assembly (101).

As mentioned above, a suture loop (104) may be releasably connected tothe snare (102). For example, as shown in FIGS. 1 and 2, the suture loop(104) may be releasably coupled to the snare (102) via a retentionmember (106). The retention member (106) may be any suitable structure,such as a dual-lumen tube or one or more of the retention membersdescribed in U.S. patent application Ser. No. 13/490,919, which waspreviously incorporated by reference in its entirety. The suture loop(104) may be initially configured to have a diameter larger than that ofthe snare loop assembly (101) when the snare loop assembly (101) isopened (excess suture of the suture loop (104) may be housed in theelongate body (108), such as described in U.S. patent application Ser.No. 13/490,919, which was previously incorporated by reference in itsentirety).

The suture loop (104) may be tightened to reduce the diameter of thesuture loop (104). When the diameter of the suture loop (104) is reducedpast the diameter of the loop (109) of the snare loop assembly (101),the suture loop (104) may disengage and be released from the snare loopassembly (101). For example, tightening the suture loop (104) may causethe suture loop (104) to pull or tear through one or more walls, slits,prongs, arms or the like of the retention member (106) to break theconnection between the suture loop (104) and the retention member (106).

Generally, the suture loop (104) may comprise a loop portion (120), asuture knot (122) and a tail (124). As shown in FIG. 2, the suture knot(122) may be temporarily held at least partially within the tip (110) ofthe elongate body (108). The suture of the loop portion (120) may bepulled through the suture knot (122) to reduce the diameter of the loopportion (120). The suture tail may extend through the elongate body(108) (e.g., through the second lumen (116) of the elongate body (108)),and may be operatively attached to a suture control (not shown). Thesuture control may be used to pull the suture tail (124), which in turnmay reduce the diameter of the loop portion (120) of the suture loop.When the snare (102) is advanced or withdrawn relative to the firstlumen (114) of the elongate body (108), a portion of the suture loop(104) and the retention member (106) may also be advanced out of orwithdrawn into the first lumen (114) of the elongate body (108). Thesuture knot (120) is preferably a one-way knot (e.g., a slip-knot),which allows the suture loop to maintain its diameter as the suture loop(104) is tightened. Additionally or alternatively, the suture loop (104)may comprise one or more unidirectional locking structures (such asthose described in U.S. patent application Ser. No. 13/490,919, whichwas previously incorporated by reference in its entirety) which may helpprevent the loop portion (120) from increasing in diameter (e.g., inresponse to expansive forces provided by the ligated tissue) of thesuture loop (104) after it is tightened.

To close a tissue (such as the left atrial appendage) with the closuredevice (100), the closure device (100) may be advanced to the targettissue. Generally, the closure devices described here may be suitablefor use using minimally invasive access to the left atrial appendage(e.g., through a small incision above, beneath or through the rib cage,through an incision in the costal cartilage or the xiphoid, through aport, through the vasculature, etc.), as discussed above. The moveableend of the snare (102) may be advanced relative to the elongate body(108) to increase the diameter of the loop (109) of the snare loopassembly (101) to “open” the snare loop assembly. With the snare loopassembly in an open configuration, the loop (109) may be placed aroundthe target tissue to encircle the tissue. The moveable end of the snare(102) may be withdrawn relative to the elongate body (108) to decreasethe diameter of the loop (109), which may close the snare loop assembly(101) around the tissue. With the tissue held in a closed configurationby the snare (102) and the snare loop assembly (101), the suture loop(104) may be tightened (i.e., the diameter of the loop portion (120) maybe reduced by pulling the tail (124) relative to the suture knot (122))to release the suture loop (104) from the snare loop assembly (101).Once released, the suture loop (104) may hold the tissue in a ligatedconfiguration, and the remaining portions of the closure device (100)may be removed. In some instances, the suture loop (104) may be furthertightened to reduce the diameter of the suture loop (104), as will bediscussed in more detail below.

As mentioned above, one or more portions of the closure systemsdescribed here may be configured to ablate or abrade left atrialappendage tissue during the closure procedures described generallyabove. Generally, left atrial appendage tissue may be ablated or abradedfrom an endocardial approach (i.e., from an interior of the heart), anepicardial approach (i.e., from an exterior of the heart), or acombination of endocardial and epicardial approaches. For the purposesof this application, “interior tissue” of the left atrial appendage orheart will refer to internal tissue surfaces of the left atrialappendage or heart, respectively, which are accessible from the interiorof the heart and/or left atrial appendage. Conversely, “exterior tissue”of the left atrial appendage or heart will refer to external tissuesurfaces of the left atrial appendage or heart, respectively, which areaccessible from an exterior of the heart and/or left atrial appendage.

When the closure systems described here comprise an inflatable balloonor other expandable member (e.g., as part of an expandable membercatheter or a first guide element), the expandable member may beconfigured to ablate or abrade tissue. FIGS. 5A-5C depict differentvariations of expandable member catheters in the form of ballooncatheters configured to provide ablation energy to tissue. It should beappreciated that each of these variations may be incorporated into aguide element having an inflatable or expandable member. FIG. 5A shows aside view of a first variation of a balloon catheter (500) having aninflatable balloon (502) (although it should be appreciated that theballoon catheter (500) may comprise any suitable inflatable orexpandable member). As shown there, the balloon (502) may comprise aplurality of abrading (e.g., a roughened surface, one or more barbs,spikes, hooks, or the like) or ablating (e.g., electrodes) elements(504) positioned around an exterior surface of the balloon (502). Invariations used for ablation, the expansion of the balloon (502) maypress one or more of the electrodes (504) against tissue, and energy maybe delivered to tissue via one or more of the electrodes (504) to ablatetissue. The energy may be delivered from any suitable energy source,including but not limited to, a transducer to deliver high-intensityfocused ultrasound to the tissue to locally heat and ablate it, a laser,an RF generator, etc. In some variations, one or more of the electrodes(504) may be configured to monitor one or more tissue parameters (e.g.,temperature, ECG signals, the presence or absence of ECG signals) duringablation. The electrodes (504) may be electrically connected to aproximal portion of the balloon catheter (500) via one or more leads(not shown) incorporated into or on a shaft (506) of the ballooncatheter (500).

In some variations, one or more of the electrodes of a balloon may beconfigured to circumferentially surround the balloon. For example, FIG.5B shows another variation of a balloon catheter (510) having a balloon(512) or other expandable member. As shown there, the balloon catheter(510) may comprise at least one electrode (514) connected to the balloon(512). As shown there, the electrode (514) may be configured tocircumferentially surround the balloon (512). In these variations, theelectrode (514) may be flexible or otherwise configured to match theshape of the balloon (512) during inflation and deflation of the balloon(512). When the balloon (512) is expanded, the balloon (512) may pressthe electrode (514) into contact with tissue, and energy may be suppliedto the tissue via the electrode (514) to ablate tissue. Thecircumferential nature of the electrode (514) may allow the electrode(514) to ablate a ring of tissue (e.g., when positioned inside of theleft atrial appendage). While shown in FIG. 5B as having a singleelectrode (514), it should be appreciated that the balloon catheter(510) may comprise a plurality of electrodes attached to the balloon(512), such as described above. The electrodes (514) may be electricallyconnected to a proximal portion of the balloon catheter (510) via one ormore leads (not shown) incorporate into or on a shaft (516) of theballoon catheter (510).

In other variations, the balloon catheter may be configured to thermallyablate tissue. For example, FIG. 5C shows another variation of a ballooncatheter (520) having a balloon (522). As shown there, the balloon (522)may be mounted to a shaft (524), and the balloon catheter (520) mayinclude one or more electrodes (526) mounted on the shaft (524) withinthe balloon (522). In these variations, fluid (e.g., saline, asaline/contrast fluid mixture) may be introduced into the balloon (522)(e.g., through an inflation port (not shown) on the shaft inside theballoon (522)) to inflate the balloon (522). RF energy may be suppliedto the one or more electrodes (526), which may heat the one or moreelectrodes (526) and the fluid in the balloon (522). In some variations,the shaft inside of the balloon (522) may comprise one or more resistiveheating elements connected to an electrical source, which may heat thefluid inside of the balloon. As the fluid in the balloon is heated,tissue in contact with the balloon may be heated to ablate the tissue.In other variations, the balloon catheter may be configured to introducea cooled fluid into the balloon (522), which may cryoablate tissue incontact with the balloon (522). In yet other variations, the ballooncatheter may be configured to introduce or apply therapeutic compounds(e.g., to promote healing) to the tissue. For example, in some instancesthe balloon (522) may comprise one or more porous materials such thatthe balloon catheter may also be used for drug delivery.

In some variations, the expandable member may comprise a loop or a metalform similar to a stent or an interior vena cava filter. For example,FIGS. 14A-14F depict embodiments of expandable members for ablating orabrading the interior tissue of the LAA. FIGS. 14A and 14B illustrate anexpandable member catheter comprising an expandable member (1414) in theform of an actuatable electrode or abrading loop (1402) that may beadvanced from a distal end of an elongate body (1406). The loop (1402)may be actuated (e.g., by an actuator (not pictured) on a handle orother control portion of the catheter) to control the size of loop(1402) (e.g., diameter and/or circumference) and the location ofablation or abrading. As can be seen in FIGS. 14A and 14B, the elongatebody (1406) may comprise a lumen (1408) through which the distal end(1410) of the loop (1402) travels to connect to the actuator. Theproximal end (1404) of the loop (1402) may be fixed to the elongate body(1406). The actuator may be configured to advance or retract the distalend (1410) of the loop (1402) relative to the elongate body (1406) tocontrol the amount of the loop (1402) extending from the elongate body(1406) and thus the size (e.g., circumference and/or diameter) of theloop (1402).

The loop (1402) may comprise a conductive material such that the loop(1402) functions as an electrode to ablate tissue when connected to anenergy source and energized. The loop (1402) may comprise a protectivecoating or sleeve which may help prevent inadvertent ablation when theloop (1402) is energized but not yet properly placed. In someembodiments, the loop (1402) may comprise ablating or abrading elements(1412), as depicted in FIG. 14B. In some variations, the ablating orabrading elements (1412) may comprise electrodes (e.g., RF electrodes).Additionally or alternatively, the ablating or abrading elements (1412)may comprise a roughened surface, one or more barbs, spikes, hooks, orthe like. In variations in which the loop (1402) itself may beenergized, the loop (1402) may also comprise abrading elements (1412).In other variations, the loop (1402) may comprise a lumen therethroughand may be connected at its distal end to a fluid source. The cryogenicfluid may flow through the loop's (1402) lumen such that the loop (1402)may be used to cryoablate the interior tissue of the LAA. In someembodiments, the loop may further comprise apertures such that the loop(1402) may deliver or dispense a therapeutic compound or an adhesive tothe internal surface of the LAA, which may assist with tissue healingand/or LAA closure.

FIGS. 14D-14F depict additional embodiments of expandable members (1414)that may be utilized with the expandable member catheter. FIG. 14Cdepicts an expandable member comprising a plurality of arms (1416)extending distally from a central hub (1418). In some embodiments, thearms (1416) may extend outward such that their distal tips form acircle, oval, hexagon, octagon, or any other desired shape. As depictedthere, each arm (1416) comprises an ablating or abrading element (1420)at its distal tip, but the arms may comprise ablating or abradingelements (1420) at any location along their lengths. Moreover, every arm(1416) need not comprise an ablating or abrading element (1420), and anynumber of ablating or abrading elements may be utilized. In somevariations, the arms (1420) may be made of a conductive material andconnected to an energy source such that the arms themselves may ablatetissue. In other variations, the expandable member (1414) may be made ofa rigid polymer and may comprise abrading or ablating elementsstrategically placed on the expandable member (1414) based on the user'sdesired ablation locations. FIG. 14D depicts another variation of anexpandable member (1414) comprising two arms (1416) supporting acircular ablating or abrading element (1420). The arms (1416) compriseprotective coverings (1422) (e.g., a sleeve, polymer coating, etc.)which may protect the tissue when the arms (1416) also comprise abradingor ablating elements, or may otherwise damage tissue undesirably. FIGS.14E and 14F depict variations of the expandable members (1414)comprising wire form or stent-like configurations and which compriserounded bodies (1424) (e.g., comprising circular, oval, etc.cross-sections) in their expanded configurations. These expandablemembers (1414) may comprise any number of abrading or ablating elements,and/or may themselves be ablating or abrading elements (e.g., the wiresthat form the bodies (1424) may ablate or abrade tissue).

The expandable members may comprise a first retracted position and asecond expanded position and may be constructed of a resilient material(e.g., a shape-memory material like nitinol) such that the expandablemembers may be advanced to the LAA in the retracted position (forexample, as shown in FIG. 15A) and may be subsequently advanced into theexpanded position (e.g., as shown in FIG. 15B) once proper placement isachieved. In the variation shown in FIGS. 15A and 15B, the expandablemember (1514) is slideably disposed within the lumen (1508) of thecatheter's elongate body (1506). The hub (1518) is connected to a secondelongate body (1502) such that a user may advance the expandable member(1514) distally relative to the catheter's elongate body (1506) to movethe expandable member from its retracted position (in which it isconstrained) to its expanded position (in which it is no longerconstrained). In some variations, the expandable member (1514) maycomprise a hub (1518) at the proximal and distal ends of its arms orbody. In these embodiments, the expandable member catheter may beconfigured such that the hub at the distal end of the expandable membercatheter may be fixed and the hub at the proximal end may slide distallysuch that the hubs at the proximal and distal ends of the expandablemember move toward each other to move the expandable element from itsretracted position to its expanded position. In some variations, theexpandable member (1514) may be coupled to the expandable membercatheter but not disposed within its lumen.

In some embodiments, the systems described here may comprise twoexpandable member catheters. For example, the system may comprise afirst expandable member catheter comprising a balloon (i.e., a ballooncatheter) and a second expandable member catheter comprising any of theexpandable members (1414) previously described (e.g., those depicted inFIGS. 14A-14F.) In these systems, a user may advance the ballooncatheter into the LAA for use with the closure device, as described indetail below, and may remove the balloon catheter once the snare loopassembly has been deployed. The second expandable member catheter maythen be advanced to the interior of the LAA specifically for the purposeof abrading or ablating tissue.

Any of the balloons described above may be used to ablate an interiortissue of the left atrial appendage. FIGS. 6A-6C depict an illustrativemethod by which a balloon may be used to ablate interior tissue of theleft atrial appendage. As shown in FIG. 6A, a first guide element (600)and a second guide element (602) may be advanced and positioned suchthat a distal end of the first guide element (600) is positioned in theleft atrial appendage (604) and a distal end of the second guide element(602) is positioned outside the left atrial appendage (604) in thepericardial space (606). The first guide element (600) and second guideelement (602) may be aligned (e.g., using one or more magnets (notshown), such as described in more detail above with respect to FIG. 4).In some variations, a balloon catheter (608) may be advanced to positiona balloon (610) in the left atrial appendage (604). In some of thesevariations, the balloon catheter (608) may be advanced along the firstguide (600) after the first guide element (600) has been positioned inthe left atrial appendage (604). In other variations, the ballooncatheter (608) may be advanced simultaneously with the first guideelement (600). In still other variations, the system may not comprise aballoon catheter (608), but instead the balloon (610) may be part of thefirst guide element (600), such that advancement of the first guideelement (600) into the left atrial appendage (604) positions the balloon(610) in the left atrial appendage (604). The balloon (610) may then beinflated inside of the left atrial appendage (604).

Additionally, a closure device (612) may be advanced along the secondguide element (602) to position a closure assembly (614) (such as asnare loop assemblies as discussed above with respect to FIGS. 1-3)around the left atrial appendage. With the balloon (610) positioned inthe left atrial appendage (604) and the closure assembly (614)positioned around the left atrial appendage (604), the closure assembly(614) may be at least partially closed to close the left atrialappendage (604) around the balloon (610). In some variations, prior toclosing the closure assembly (614), the balloon (610) and the closureassembly (614) may be positioned such that the balloon (610) ispositioned inside of the closure assembly (614).

In other variations, the balloon (610) and closure assembly (614) may beinitially positioned such that the closure assembly (614) is advancedpast the balloon (610) and is positioned around a portion of the ballooncatheter (608) (or the first guide element (600) in variations where theballoon (610) is part of the first guide element (600)) proximal of theballoon (610), such as shown in FIG. 6A. In these variations, theclosure assembly (614) may be partially closed around the left atrialappendage (604) with the balloon (610) inflated to partially grab theleft atrial appendage (604). With the closure assembly (614) engagingthe left atrial appendage, the balloon (610) may be deflated andretracted (by retracting the balloon catheter (608), or the first guideelement (600) in variations where the balloon (610) is part of the firstguide element (600)) to position the balloon (610) inside of the closureassembly (614). The balloon (610) may be re-inflated to press theballoon (610) in contact with the interior tissue of the left atrialappendage (604), such as shown in FIG. 6B. In some of these variations,the closure assembly (614) may also be further closed to further pulltissue of the left atrial appendage (604).

With the left atrial appendage (604) closed around the balloon (610),the balloon (610) may be used to ablate or abrade the interior tissuethat is captured by the closure assembly (614). This ablation orabrading may be done in any suitable manner. In variations where theballoon (610) comprises one or more electrodes (such as the electrodes(504) of the balloon (502) described above with respect to FIG. 5A orthe electrode (514) of the balloon (512) described above with respect toFIG. 5B), the left atrial appendage (604) may be closed around theballoon (610) to press the interior tissue of the left atrial appendagein contact with some or all of the electrodes. RF energy may be suppliedto the electrodes (514) to ablate the interior tissue. In variationswhere the balloon (610) includes one or more electrodes positionedwithin the balloon (such as the balloon (522) described above withrespect to FIG. 5C), the electrodes may be used to heat a fluid in theballoon (610) such that the heat is transferred from the balloon to theinterior tissue of the left atrial appendage (604) that is in contactwith the balloon (610) to ablate tissue. In variations in which a cooledfluid is introduced into the balloon, the balloon may be used tocryoablate the interior tissue of the left atrial appendage (604) thatis in contact with the balloon (610). In variations in which the ballooncomprises abrading elements, the abrading elements may be used tophysically damage or abrade tissue when moved against the tissue. Invariations in which the balloon comprises porous materials, the balloonmay be used to locally deliver therapeutic compounds to the surroundingtissue.

Following tissue ablation, the balloon (610) may be deflated and removedfrom the left atrial appendage (e.g., the first guide element (600) maybe removed from the left atrial appendage, as well as the ballooncatheter (608) in variations where the balloon (610) is part of theballoon catheter (608)). The closure assembly (614) may then be furtherclosed to fully close the left atrial appendage (604), such as shown inFIG. 6C. In some variations, a suture loop or similar device may bedeployed from the closure assembly (614) to maintain the left atrialappendage (604) in a closed configuration.

In other variations, one or more portions of the shaft of a ballooncatheter or guide element may be used to ablate or abrade tissue. FIG.7A shows one such variation of a balloon catheter (700) as describedhere. As shown there, the balloon catheter (700) may comprise a shaft(702), a balloon (704), and one or more electrodes or abrading elements(706) positioned on the shaft (702) proximally of the balloon (704).While shown in FIG. 7A as having a plurality of electrodes or abradingelements (706), in some variations the balloon catheter (700) may onlycomprise a single electrode or abrading element (706). In somevariations, a balloon catheter may comprise at least one electrode andat least one abrading element positioned on a shaft of the ballooncatheter proximal to the balloon. In some variations, elements (706) maycomprise magnets, electromagnets, or magnetic material which may helpwith proper placement of the closure device, and more specifically, thesnare loop assembly of the closure device, in embodiments in which theclosure device comprises magnetic material. Elements (706) may be anycombination of ablating, abrading, and magnetic elements. As discussedabove, the ablating or abrading elements need not necessarily beincorporated on the balloon catheter and could instead be on a separatedevice that is advanced into the LAA after the balloon catheter isremoved, but before the suture loop is deployed.

As mentioned above, the balloon catheter may comprise one or moreabrading elements positioned on the shaft of the balloon catheter. Forexample, FIG. 7B shows one such variation of a balloon catheter (710),where the balloon catheter (710) may comprise a shaft (712), a balloon(714), and an abrading element (716) positioned on the shaft (712)proximal to the balloon (714). The abrading element (716) is generallyconfigured such that it may physically damage or abrade tissue whenmoved against the tissue, as will be discussed in more detail below. Forexample, the abrading element (716) may include a roughened surface, oneor more barbs, spikes, hooks, or the like.

In variations where a guide element comprises a balloon (e.g., in placeof having a separate balloon catheter), the guide element may compriseone or more electrodes and/or abrading elements positioned on the guideelement proximally of the balloon. For example, FIG. 7C shows avariation of guide element (720) having a balloon (722) and one or moreelectrodes (724) positioned on the guide element (720) proximally of theballoon (722). FIG. 7D shows another variation of a guide element (730)having a balloon (732) and one or more abrading elements (734)positioned on the guide element (730) proximally of the balloon (732).In these variations, the guide element may comprise any number andcombination of electrodes and or ablation elements, such as describedabove.

When a balloon catheter or guide element comprises a balloon and one ormore electrodes and/or abrading elements proximally to the balloon, theelectrodes and/or abrading elements may ablate and/or abrade,respectively, interior tissue of the left atrial appendage. For example,FIGS. 8A and 8B depict such an illustrative closure method. As shown inFIG. 8A, a balloon (800) may be advanced into the left atrial appendage(802). In some variations, the balloon (800) may be part of a ballooncatheter (804) (such as the balloon catheter (700) described above withrespect to FIG. 7A or the balloon catheter (710) described above withrespect to FIG. 7B), and the balloon catheter (804) may be advancedalong a first guide element (806), such as described above. In othervariations, the balloon (800) may be part of the first guide element(such as the guide element (720) shown in FIG. 7C or the guide element(730) shown in FIG. 7D), such that advancement of the first guideelement (806) into the left atrial appendage (802) also positions theballoon (800) in the left atrial appendage.

A closure device (808) may be advanced externally of the heart toposition a closure assembly (810) of the closure device (808) aroundexternal tissue of the left atrial appendage (802). The closure device(808) may be advanced in any suitable manner, such as, for example,along a second guide element (812) that is positioned in the pericardialspace, such as discussed in more detail above (the first and secondguide elements may include magnets that may align the first and secondguide elements across tissue of the left atrial appendage). Generally,the closure device (808) may be advanced to position the closureassembly past the balloon (800) (e.g., such that the closure device(808) is positioned around a portion of the balloon catheter (804)and/or first guide element (806) proximal to the balloon (800)), such asshown in FIG. 8A. As mentioned above, the balloon catheter (804) (orfirst guide element (806) in variations where the balloon (800) is partof the first guide element (806)) may comprise one or more elements(814), which may include one or more electrodes and/or abradingelements, such as discussed above.

With the closure device (808) and balloon (800) positioned as shown inFIG. 8A, the closure assembly (810) may be closed to place the leftatrial appendage into contact with one or more of the elements (814). Invariations where the one or more elements (814) comprise an electrode,the electrode may be activated to ablate the interior left atrialappendage tissue in contact with the electrodes. In variations where theone or more elements (814) comprise an abrading element, the abradingelement may be moved relative to the interior left atrial appendagetissue to abrade that issue. In some variations, this may compriserotating and/or longitudinally translating the balloon catheter (804)(or the first guide element (806) in variations where the abradingelement is part of the first guide element (806)) to move the abradingelement relative to the tissue to abrade the interior tissue of the leftatrial appendage. In other variations, the abrading element may bemoveable relative to the balloon catheter (804) and/or the first guideelement (806), and may be actuated to move the abrading element relativeto tissue to abrade the tissue.

Once the tissue has been abraded and/or ablated, the balloon (800), theballoon catheter (804) (in variations where the balloon (800) is part ofthe balloon catheter (804), and the first guide element (806) may beremoved, and the closure assembly (810) may be further closed to closethe left atrial appendage (802), as shown in FIG. 8B.

In some variations, the distal end of a guide element may be configuredto ablate interior tissue of the left atrial appendage. For example,FIG. 9A shows a variation of a guide element (900) as described here. Asshown in FIG. 9A, the guide element may comprise a magnet (902)positioned at a distal end of the guide element (900). Also shown thereis an electrode (904) positioned at a distal end of the guide element(900). The electrode may be used to ablate interior tissue of the leftatrial appendage, as will be described in more detail below. In someembodiments, the guide element may be configured to deliver or dispensefluid to surrounding tissue.

In other variations, a wire or other member may be advanced from adistal end of the guide element, and may be configured to act as anelectrode to ablate tissue. For example, FIG. 9B shows another variationof a guide element (910) as described here. As shown there, the guideelement (910) may comprise a magnet (912) at a distal end of the guideelement (910), and may comprise a lumen (914) extending through theguide element (910). The guide element (910) may further comprise a wire(916) which may be advanced through the lumen (914) to extend from adistal end of the guide element (910). A proximal end of the wire (916)may be connected to an energy source (not shown) such that the wire(916) may act as an electrode to ablate tissue. In some variations, aproximal end of the wire (916) may be connected to a source of cryogenicfluid such that the wire (916) may be used to cryoablate tissue. In someembodiments, the wire (916) may comprise a lumen such that it may beused to dispense fluid to the surrounding tissue. The fluid may bedelivered through the lumen and either out of the distal tip of the wire(916) or through side apertures along the wire's distal end. Theproximal end of the wire (916) may be connected to a source of fluid,for example, a therapeutic compound or an adhesive, and the wire (916)may be used to deliver and dispense the fluid to locally affect (e.g.,promote healing or closure) the surrounding tissue. The wire (916) maybe any suitable wire. For example, the wire (916) may be a straight-tipor j-tip wire, may be a coiled wire, or may be configured to makeanother 3-dimensional shape. In some of these variations, the wire maybe a ball-tipped wire.

When a guide element has an electrode or electrode wire at its distalend (such as the guide elements (900) and (910) described above withrespect to FIGS. 9A and 9B, respectively), the guide element may be usedto ablate interior tissue of the left atrial appendage. For example,FIGS. 10A-10C shows two such variations of a method of closing a leftatrial appendage. As shown in FIG. 10A, a first guide element (1000) maybe positioned inside the left atrial appendage (1002) and a second guideelement (1004) may be positioned externally of the left atrial appendage(1002) in the pericardial space (1006). In some variations, the firstguide element (1000) and the second guide element (1004) may be alignedusing magnets on each of the guide elements, such as discussed in moredetail above. A closure device (1008) may be advanced over the secondguide element (1004) to position a closure assembly (1010) aroundexterior tissue of the left atrial appendage (1002). In some variations,a balloon (1018) may be positioned in the left atrial appendage (1002)(either as part of a balloon catheter (1012) or the first guide element(1000)), such as discussed in more detail below.

With the closure assembly (1010) of the closure device (1008) encirclingthe left atrial appendage (1002), the first guide element (1000) (andthe balloon catheter (1012) in variations where a balloon catheter(1012) is at least partially advanced into the left atrial appendage(1002)) may be removed from the interior of the left atrial appendage(1002) and the closure assembly (1010) may be closed to close the leftatrial appendage. After the left atrial appendage (1002) is closed, thefirst guide element (1000) may be re-advanced to ablate, join or bond,or deliver drugs to the closed left atrial appendage tissue.

For example, in variations where the first guide element (1000)comprises an electrode (1014) at a distal end of the first guide element(1000), the first guide element (1000) may be re-advanced to place theelectrode (1014) into contact with the interior tissue of the leftatrial appendage (1002), as shown in FIG. 10B. Generally, this may placethe electrode (1014) into contact with tissue around the ostium of theleft atrial appendage (1000). The electrode (1014) may deliver RF energyto the tissue of the left atrial appendage (1002) to ablate the tissue.In some variations, the first guide element (1000) may be used withcryogenic fluid to cryoablate tissue. In some embodiments, the closuredevice (1008) may comprise a magnetic tip (e.g., tip (110) depicted inFIG. 1) or a magnet on its distal end to assist in guiding the distalend of the first guide element (1000) into contact with the interiortissue of the left atrial appendage (1002) in embodiments in which thefirst guide element (1000) comprises a magnet, as described above.

In variations where the first guide element (1000) is configured toadvance a wire (1016) out of a distal end of the first guide element(1000), the wire (1016) may be advanced from a distal end of the firstguide element (1000) to expose a portion of the wire (1016), and thewire (1016) may be positioned in contact with the tissue around theostium of the left atrial appendage (1002), such as shown in FIG. 10C.In some instances this may comprise advancing the first guide element(1000) and the wire (1016) together. With the wire (1016) in contactwith left atrial appendage tissue, the wire (1016) may be activated asan electrode to ablate the tissue, may be used with cryogenic fluid tocryoablate the tissue, or may be configured to locally deliver fluid, asdescribed above.

It should be appreciated that the methods described above with respectto FIGS. 10A-10C may be used with any of the methods described abovewith respect to FIGS. 6A-6C and 8A-8B. In these variations, interiortissue of the left atrial appendage may be ablated or abraded, and maybe closed to press the ablated/abraded tissue into contact with itself(which may assist in electrical isolation and/or invoking a healingresponse). The closed ostium of the left atrial appendage may then beablated or abraded to further promote electrical isolation of the leftatrial appendage and/or a healing response.

In addition to or as an alternative to ablating or abrading the interiortissue of the left atrial appendage, the closure devices described heremay be configured to ablate exterior tissue of the left atrialappendage. FIGS. 11A-11C show cross-sectional side views of a distalportion of one such variation of a closure device (1100). As shownthere, the closure device (1100) may comprise an elongate body (1102)and a snare loop assembly (1104), which may define a loop (1106)encircling an aperture (1108). The snare loop assembly (1104) maycomprise a snare (1110), a suture loop (1112), and retention member(1114), such as discussed in more detail above. The suture loop (1112)may include a tail portion (1116), a suture knot (1118), and a loopportion (1120), such that one end of the snare (1110) extends through afirst lumen (1124) in the elongate body (1102) and the tail portion(1116) of the suture loop (1112) extends through a second lumen (1122)in the elongate body. A second end (1126) of the snare (1110) may befixed relative to the elongate body (1102). As discussed in more detailabove, movement of the snare (1110) into and out of the first lumen(1124) may increase and decrease the size of the loop (1106) defined bythe snare loop assembly (1104).

Also shown in FIGS. 11A-11C is an electrode (1128). The electrode (1128)may be positioned around a portion of the snare loop assembly (1006). Inthe variation shown in FIGS. 11A-11C, the electrode (1128) may bepositioned on the snare (1110) between the fixed end (1126) of the snare(1110) and the retention member (1114), but not around the suture loop(1112). In some variations, a portion of the snare (1110) may act as anelectrode (1128). Specifically, the snare (1110) may be formed from anelectrically conductive material which may convey current from aproximal portion of the snare to the electrode (1128). The snare (1110)may be at least partially covered with an insulating material (such asPTFE), such that the insulating material insulates portions of the snare(1110) to prevent inadvertent ablation by the snare. The electrode(1128) may not include the insulating material to expose the conductivematerial of the snare (1110), which may thereby act as an electrode. Itshould be appreciated that the snare may also be used with cryogenicfluid (e.g., within a lumen of the snare) such that the snare maycryoablate the tissue. The snare may also comprise porous materials orapertures such that the snare may be used to dispense therapeuticcompounds, adhesive, or any other desired material to the tissue.Moreover, in some variations, the electrode (1128) may comprise magneticmaterial or may be an electromagnet. In these variations, when the snare(1110) is closed around the external surface of the left atrialappendage, the magnetic material of electrode (1128) may externallyencircle the left atrial appendage which may assist in guiding a tool(e.g., an ablation or abrading device) within the left atrial appendageor the left atrium to the closure site.

While shown in FIGS. 11A-11C as having a single electrode (1128), theclosure device 1100) may comprise any suitable number of electrodes(e.g., one, two, three, or four or more electrodes). For example, FIGS.12A-12C show another variation of a closure device (1200) having aplurality of electrodes (1202). The closure device (1200) may comprise asnare loop assembly (1104) and an elongate body (1102) as discussedabove with respect to FIGS. 11A-11C (identical components are labeled asshown in FIGS. 11A-11C). As shown in FIGS. 12A-12C, the closure devicemay include a plurality of electrodes (1202) positioned on the snare(1110) between the fixed end (1126) of the snare (1110) and theretention member (1114). While shown in FIGS. 12A-12C as having fiveelectrodes (1202), the snare (1110) may include any suitable number ofelectrodes as discussed above. In variations where the snare (1110)includes multiple electrodes (1202), some electrodes may be used toablate tissue, while other electrodes may be used to monitor one or moreaspects of tissue (e.g., one or more electrical signals, temperature, orthe like).

Additionally, as described above with respect to electrode (1128),electrodes (1202) may comprise magnetic material or electromagnets.Moreover, in some variations, one or more of the elements (1202) may bereplaced by magnets. In variations in which the elements (1202) compriseboth electrodes and magnets, the electrodes and magnets may be arrangedalong the snare in any suitable configuration, for example, alternatingevery other element, in pairs, in groups, etc. The magnets may assist auser in locating the desired area inside of the heart as the magnets onthe snare may help align a tool inside of the heart with the closurelocation. Additionally, in embodiments in which the elements (1202)comprise both magnets and electrodes, a user may ablate an externalsurface of the left atrial appendage with the electrodes and utilize themagnets to align an internal tool (ablating, abrading, or other tissueaffecting device) with the external electrodes to ablate or otherwiseaffect the tissue at substantially the same location.

The closure devices (1100) and (1200) shown in FIGS. 11A-11C and 12A-12Crespectively, may be used to ablate tissue of the left atrial appendage.For example, the snare loop assembly (1104) may be placed in an openconfiguration, as shown in FIGS. 11A and 12A, and may be advanced intothe pericardial space to position the left atrial appendage (not shown)in the aperture (1108) of the snare loop assembly. The snare loopassembly (1104) may be closed around the left atrial appendage to closethe left atrial appendage, as shown in FIGS. 11B and 12B. This mayposition the electrode (1128) (in the instance of the closure device(1100)) or one or more of the electrodes (1202) (in the instance of theclosure device (1200)) in contact with exterior tissue of the leftatrial appendage. In some instances, the exterior tissue of the leftatrial appendage may be ablated at this point.

In some variations, the suture loop (1112) may be tightened to releasethe suture loop from the retention member (1114) and the snare loopassembly (1104), such as shown in FIGS. 11C and 12C. In some variations,the exterior tissue of the left atrial appendage may be ablated usingthe electrode (1128) or one or more of the electrodes (1202) after thesuture loop (1112) has been released from the snare loop assembly(1104). This may be done in addition to or instead of ablation prior tothe release of the suture loop (1112). In some variations, the snareloop assembly (1104) may be reclosed around the left atrial appendageprior to ablation to tighten the snare loop assembly (1104) againsttissue. In some variations, the snare loop assembly (1104) may bereopened, repositioned, and reclosed around the left atrial appendageprior to ablation.

The closure device (1300) depicted in FIGS. 13A-13C may be used toabrade tissue of the left atrial appendage. As shown there, the closuredevice (1300) comprises a snare loop assembly (1304) similar to thatdescribed with respect to FIGS. 11A-11C and 12A-12C above, except thatthe snare loop assembly (1304) comprises a plurality of abradingelements (1302) instead of, or in addition to, a plurality ofelectrodes. The abrading elements (1302) may be disposed on an abradingmember (1316) (e.g., tubing) that is slideably disposed on the snare.The abrading member (1316) may be coupled to an actuator (not depicted)on the handle or control element of the closure device (1300) throughcontrol wires (1318). A user may actuate the abrading member (1316) byalternatingly pulling the control wires (1318) such that the abradingmember (1316) slides along the snare (1310). The abrading elements(1302) fixed to the abrading member (1316) are thus moved in areciprocating motion and may be used to abrade tissue. It should beappreciated that the abrading elements (1302) may also comprise one ormore electrodes to ablate tissue.

We claim:
 1. A method of closing a left atrial appendage comprising:advancing a snare loop assembly to the left atrial appendage, the snareloop assembly comprising a snare loop and suture loop releasably coupledto the snare loop; partially closing the snare loop assembly around theleft atrial appendage; ablating the left atrial appendage for a firstperiod of time after partially closing the snare loop assembly; furtherclosing the snare loop assembly around the left atrial appendage toclose the left atrial appendage; ablating the left atrial appendage fora second period of time after further closing the snare loop assembly;and releasing the suture loop from the snare loop assembly.
 2. Themethod of claim 1, wherein ablating the left atrial appendage for afirst period of time comprises ablating an internal surface of the leftatrial appendage.
 3. The method of claim 1, wherein ablating the leftatrial appendage for a second period of time comprises ablating anexternal surface of the left atrial appendage.
 4. The method of claim 1,wherein ablating the left atrial appendage for a second period of timecomprises ablating the left atrial appendage with the snare loop.
 5. Themethod of claim 4, wherein the snare loop comprises an electricallyconductive portion and an insulated portion.
 6. The method of claim 4,wherein the snare loop assembly comprises an electrode positioned on aportion of the snare loop.
 7. The method of claim 1, wherein the leftatrial appendage is ablated during both the first time period and thesecond time period using RF energy.
 8. The method of claim 1 furthercomprising positioning a distal portion of a first guide element in apericardial space.
 9. The method of claim 8, wherein advancing the snareloop assembly comprises advancing the snare loop assembly along thefirst guide element.
 10. The method of claim 8 further comprisingpositioning a distal portion of a second guide element in the leftatrial appendage.
 11. The method of claim 10, wherein the first guideelement comprises a first magnet and the second guide element comprisesa second magnet and the method further comprises aligning the first andsecond guide elements across the left atrial appendage using the firstand second magnets.
 12. A method of ablating a left atrial appendagecomprising: advancing a snare loop assembly around the left atrialappendage, the snare loop assembly comprising an ablation loop and asuture loop releasably coupled thereto; closing the snare loop assemblyaround the left atrial appendage; ablating the left atrial appendagewith the ablation loop for a first period of time; adjusting at least aportion of the snare loop assembly around the left atrial appendage; andablating the left atrial appendage with the ablation loop for a secondperiod of time after adjusting at least a portion of the snare loopassembly.
 13. The method of claim 12, wherein the snare loop assembly isadvanced around the left atrial appendage from a sub-xiphoid approach.14. The method of claim 12, wherein the snare loop assembly furthercomprises a retention member releasably coupling the suture loop to theablation loop.
 15. The method of claim 12 further comprising releasingthe suture loop from the snare loop assembly.
 16. The method of claim12, wherein the left atrial appendage is ablated during both the firsttime period and the second time period using RF energy.
 17. The methodof claim 12, wherein the left atrial appendage is ablated during boththe first time period and the second time period using cryogenic fluid.18. The method of claim 12 further comprising positioning a distalportion of a first guide element in a pericardial space.
 19. The methodof claim 18, wherein advancing the snare loop assembly comprisesadvancing the snare loop assembly along the first guide element.
 20. Themethod of claim 18 further comprising positioning a distal portion of asecond guide element in the left atrial appendage.
 21. The method ofclaim 20, wherein the first guide element comprises a first magnet andthe second guide element comprises a second magnet and the methodfurther comprises aligning the first and second guide elements acrossthe left atrial appendage using the first and second magnets.